INSIDE STORY: Anna Nicole Smith's Tragic Last Days

As the new spokesmodel for Trimspa diet pills in 2003, Anna Nicole Smith was a bubbly picture of health. But just four years later, at 39 years old, the former blonde bombshell drifted out of consciousness in a Florida hotel room – too weak to walk, sit up or even drink from a glass, until her heart stopped.

What had happened?

Prosecutors blame a battery of 44 different medications provided by some of the people closest to her: the man who claimed to love her more than anyone in the world; a psychiatrist who claims she was trying to help the former Playmate endure the recent death of her son, Daniel; and Smith's own physician.

For the first time, many of the tragic details of Smith's final hours are being revealed in court. The first witnesses took the stand this week in Los Angeles to determine whether Howard K. Stern, 40, Khristine Eroshevich, 61, and Sandeep Kapoor, 41, should stand trial on felony charges of conspiring to give dangerous drugs to an addict through fraudulent means, such as by using fake names.

Powerful, Tragic Testimony

The hearing, which follows a two-year investigation into Smith's death, began with a bang. Maurice Brighthaupt, Smith's security guard, described watching Smith slurp from a baby bottle of the powerful sedative chloral hydrate – cited by a coroner as a primary cause of Smith's fatal overdose – as if it were a Pepsi.

"I saw her use a spoon maybe twice and after that it was bottle to mouth. Gulp," Brighthaupt, also a Miami firefighter, testified, adding that he had several conversations with Eroshevich in which the psychiatrist expressed concern about Smith overdosing.

Stern's lawyer says he trusted Smith's doctors to prescribe what she needed for her physical pain and is not liable for the way they obtained the drugs.

Doctors to Blame?

"I don't think anyone can say that Howard K. Stern didn't love Anna and didn't attempt, in his way, to do the best thing for her," Stern's attorney, Steven Sadow of Atlanta, tells PEOPLE.

Howard K. Stern

Stern has pleaded not guilty to 11 felony counts, including prescribing, administering or dispensing a controlled substance to an addict, obtaining a prescription for opiates by fraud, deceit or misrepresentation, and conspiracy to commit a crime. Eroshevich and Kapoor are each charged with six felony counts, including unlawfully prescribing a controlled substance, prescribing, administering or dispensing a controlled substance to an addict and conspiracy to commit a crime.

The case is far from a slam dunk for prosecutors, and even Superior Court Judge Robert J. Perry has wondered aloud about placing criminal liability on doctors and a friend: "Whose fault is it that somebody takes too many pills?"

Deputy District Attorney Renee Rose replied that the defendants were "fully aware" that Smith was an addict who could not control herself around drugs.

"It's like putting a gun in the hand of someone who is suicidal and saying don't pull the trigger," Rose says.

Sad Scene at the Hotel

Special Agent Danny Santiago of California's Bureau of Narcotics Enforcement says that Smith was clearly ill when she checked into the Seminole Hard Rock Casino in Hollywood, Fla., on Feb. 5, 2007. Santiago testified a hotel clerk told him that Smith, a repeat customer, leaned on Stern to walk and seemed "out of it."

Another hotel employee assigned to act as Smith's personal assistant recalled Eroshevich telling her that Smith had the flu. The psychiatrist said she wasn't licensed in Florida and needed help in getting a prescription for the model, Santiago said.

The hotel dispatched a local doctor to go to the room and treat Smith, but then Stern insisted the doctor stay away, citing concerns about negative press coverage.

Baby Bottle and Injections

He said that when detectives asked Stern where Smith's baby was, he told them Dannielynn had stayed behind in the Bahamas. When asked about a baby bottle at Smith's bedside, Stern replied that "she was so weak that that was the only way she could drink the Pedialyte" – a rehydrating drink for children.

Stern, a lawyer who became Smith's fiancé, knew about her use of chloral hydrate and would pass her the bottle when she asked for it, Brighthaupt testified.

Brighthaupt said he also saw Stern inject Smith with other medication "more than seven times" and recounted seeing Stern in a bathroom using a cigarette lighter and a spoon to melt Valium into an injectable form. "They felt it would get in her system faster," he said.

Smith's autopsy blamed her death on an acute combination of toxic drugs, especially chloral hydrate, Benadryl, clonazepam, diazepam and lorazepam.